Coronal holes are regions in the sun’s atmosphere where the magnetic field peels back and allows solar wind to escape.

Since our last encounter with this hole in late October it has been transiting the farside of the sun, carried around by the sun’s 27-day rotation. Now that it is back we can see that the hole is not quite as large as it was a month ago–but it is still impressive, covering more than 1/4th of the visible solar disk.